<html>
<body>
<canvas id="c" width=800 height=1000></canvas>
<script>
var canvas = document.getElementById('c');
let ctx = canvas.getContext("2d");
ctx.fillRect(40, 0, 10, 50);
ctx.fillRect(60, 100, 50, 10);
ctx.fillRect(200, 200, 20, 10);
</script>
</body>
</html>
